The Neuroscience of Effort

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The Neuroscience of Effort

While writing this post, I will get bored. I will get tired of looking at these words and crave a distraction. And so I will click away from this page and head somewhere else, amusing myself with a totally irrelevant website. After a few lovely minutes of wasted time, my feelings of guilt will grow and I will find my way back here, to this sentence.

Such are the moment-by-moment melodramas of work. It's a constant cycle of intrinsic motivation battling against extrinsic tedium, persistence against pleasure. We know what we need to do. And yet, it's always so much easier to do what we want to do.

Given the importance of this mental tug of war, I've always been deeply curious about how it unfolds inside my head. A fascinating new paper in the Journal of Neuroscience led by Michael Treadway at Vanderbilt University begins to unpack the mystery. It's a first draft of what happens in the brain as we choose between effort and indulgence, work and distraction.

The experiment utilized a simple protocol. Twenty five subjects were asked to choose between an easy or hard task that involved pushing a button. (Sounds fun, right?) Easy tasks earned $1 while the payout for hard tasks ranged from $1 to $4.30. After selecting their degree of difficulty, subjects were told that their reward was not guaranteed, and that they actually had a low (12%), medium (50%) or high (88%) chance of getting paid. The tasks themselves lasted for 30 seconds and were mind-numbingly tedious: subjects were asked to either press a button with their dominant hand 30 times in seven seconds (easy condition) or 100 times in twenty-one seconds with their non-dominant pinky finger. Such a chore makes writing look like a day at the beach.

While the bored students were frantically pressing buttons, the scientists were monitoring changes in their brain using a modified PET scan able to track the activity of dopamine neurons throughout the cortex. This allowed the scientists to search for correlations between dopaminergic activity and the willingness of subjects to pursue the least pleasurable forms of labor. They could see why some people stopped pressing the buttons while others persisted, even after their pinky began to ache.

The first thing Treadway and colleagues discovered is that subjects showing greater dopaminergic activity in the left striatum and ventromedial prefrontal cortex were more willing to work hard in exchange for greater rewards. These differences were especially striking when the probability of a payout was low. Although the odds are actually getting the money were minuscule, these subjects found a way to stay motivated. This result isn't too surprising, since several other brain scanning studies have linked these regions to cost-benefit analysis, as the brain automatically calculates whether or not a certain alternative (say, pressing a button 100 times for cash) is worth the expense, which in this case is effort. Although we're not consciously aware of these calculations, they determine whether we finish this sentence or go play Angry Birds.

But that's not the only interesting correlation uncovered by the PET scans. The scientists also discovered a surprising inverse relationship between dopamine activity in the insula and the willingness to exert effort. In short, an excited insula appears to make us lazier. While the precise function of the insula remains unclear - it is activated in all sorts of different fMRI studies - the Vanderbilt scientists argue that, at least in this case, the insula appears to representing "response costs," or the pain of having to suffer through an unpleasant task. Perhaps it detects the ennui of boredom, or the throb of that tired finger, or that existential ache of having to do something we don't want to do. Who knows? What appears to be the case is that more dopaminergic activity in the insula makes the pain of labor more salient, and that's why we quit.

Because work isn't fun. It doesn't matter if we're engaging in deliberate practice or studying algebra - the most necessary activities are often the least pleasant. Furthermore, success requires that people learn how to exert effort for extended periods of time, engaging in 10,000 hours of practice (+/- 5000 hours), suffering through 12 years of school and going through draft after draft. There are no shortcuts: even those blessed with raw talent still need to stay on task. Practice is never optional.

Consider the work of Francis Galton, the 19th century British polymath who spent decades amassing biographical information on the lives of eminent judges, politicians, poets, musicians and wrestlers. Although Galton hoped to identify the hereditary origins of genius - he wanted to lend support to his cousin Charles Darwin's new theory of evolution - he eventually concluded that innate intelligence was not sufficient for high-achievement. Rather, these successful men needed to also be blessed with "zeal and with capacity for hard labour."

This study is a first glimpse into those essential qualities described by Galton, helping us map out the individual differences that make it slightly easier for some people to engage in hard labor. These diligent souls seem to get a bit more pleasure from the possibility of reward, but they also seem less sensitive to their inner complainer, that disruptive voice reminding them that minesweeper is more fun than editing, or that the ballgame on television is much more entertaining than their homework. At any given moment, there is a tug of war unfolding in our head, determining whether or not we're willing to put in the effort. This sentence only exists because, for a few minutes at least, I was able to win the war.